[PATCH 0/9] Fix runtime pm ref leaks

[PATCH 0/9] Fix runtime pm ref leaks

[Lukas Wunner]

In preparation for runtime pm on muxed dual GPU laptops,
I've fixed all runtime pm ref leaks I could find in nouveau,
radeon and amdgpu.

To ease reviewing, I've pushed this series to GitHub:
https://github.com/l1k/linux/commits/drm_runpm_fixes_v1

@Alex Deucher: I do not have an AMD GPU so couldn't test this
beyond verifying that it compiles. Please double-check the patches
and test them internally at AMD. By the way, I've noticed that
nouveau takes a runtime pm ref in ->preclose and releases it in
->postclose. This is missing in radeon and amdgpu. Please check
if it is needed.

Thanks,

Lukas

Lukas Wunner (9):
  drm/nouveau: Don't leak runtime pm ref on driver unload
  drm/nouveau: Forbid runtime pm on driver unload
  drm/radeon: Don't leak runtime pm ref on driver unload
  drm/radeon: Don't leak runtime pm ref on driver load
  drm/radeon: Forbid runtime pm on driver unload
  drm/amdgpu: Don't leak runtime pm ref on driver unload
  drm/amdgpu: Don't leak runtime pm ref on driver load
  drm/amdgpu: Forbid runtime pm on driver unload
  drm: Turn off crtc before tearing down its data structure

 drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c | 12 +++++++++---
 drivers/gpu/drm/drm_crtc.c              | 13 ++++++++++++-
 drivers/gpu/drm/nouveau/nouveau_drm.c   |  6 +++++-
 drivers/gpu/drm/radeon/radeon_device.c  |  4 ++++
 drivers/gpu/drm/radeon/radeon_kms.c     |  5 ++++-
 5 files changed, 34 insertions(+), 6 deletions(-)

-- 
2.8.1

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[PATCH 5/9] drm/radeon: Forbid runtime pm on driver unload

[Lukas Wunner]

The PCI core calls pm_runtime_forbid() on device probe in pci_pm_init(),
making this the default state when radeon is loaded.
radeon_driver_load_kms() therefore calls pm_runtime_allow(), but there's
no pm_runtime_forbid() in radeon_driver_unload_kms() to balance it. Add
it so that we leave the device in the same state that we found it.

This isn't a bug, it's just good housekeeping. When radeon is first
loaded with runpm=1, then unloaded and loaded again with runpm=0,
pm_runtime_forbid() will be called from radeon_pmops_runtime_idle() or
radeon_pmops_runtime_suspend(), so the behaviour is correct. If there
ever is a third party driver for AMD cards, this commit avoids that it
has to clean up behind radeon.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
---
 drivers/gpu/drm/radeon/radeon_kms.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c
index 51998a4..835563c 100644
--- a/drivers/gpu/drm/radeon/radeon_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_kms.c
@@ -65,6 +65,7 @@ int radeon_driver_unload_kms(struct drm_device *dev)
 
 	if (radeon_is_px(dev)) {
 		pm_runtime_get_sync(dev->dev);
+		pm_runtime_forbid(dev->dev);
 	}
 
 	radeon_kfd_device_fini(rdev);
-- 
2.8.1

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[PATCH 3/9] drm/radeon: Don't leak runtime pm ref on driver unload

[Lukas Wunner]

radeon_driver_load_kms() calls pm_runtime_put_autosuspend() if
radeon_is_px(dev), but radeon_driver_unload_kms() calls
pm_runtime_get_sync() unconditionally. We therefore leak a runtime pm
ref whenever radeon is unloaded on a non-PX machine or if runpm=0. The
GPU will subsequently never runtime suspend after loading radeon again.

Fix by taking the runtime pm ref under the same condition that it was
released on driver load.

Fixes: 10ebc0bc0934 ("drm/radeon: add runtime PM support (v2)")
Cc: Dave Airlie <airlied@redhat.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
---
 drivers/gpu/drm/radeon/radeon_kms.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c
index 414953c..51998a4 100644
--- a/drivers/gpu/drm/radeon/radeon_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_kms.c
@@ -63,7 +63,9 @@ int radeon_driver_unload_kms(struct drm_device *dev)
 	if (rdev->rmmio == NULL)
 		goto done_free;
 
-	pm_runtime_get_sync(dev->dev);
+	if (radeon_is_px(dev)) {
+		pm_runtime_get_sync(dev->dev);
+	}
 
 	radeon_kfd_device_fini(rdev);
 
-- 
2.8.1

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[PATCH 7/9] drm/amdgpu: Don't leak runtime pm ref on driver load

[Lukas Wunner]

If an error occurs in amdgpu_device_init() after adev->rmmio has been
set, its caller amdgpu_driver_load_kms() will skip runtime pm
initialization and call amdgpu_driver_unload_kms(), which acquires a
runtime pm ref that is leaked.

Balance by releasing a runtime pm ref in the error path of
amdgpu_driver_load_kms().

Fixes: d38ceaf99ed0 ("drm/amdgpu: add core driver (v4)")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
index 9b1f979..0db692e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
@@ -137,9 +137,12 @@ int amdgpu_driver_load_kms(struct drm_device *dev, unsigned long flags)
 	}
 
 out:
-	if (r)
+	if (r) {
+		/* balance pm_runtime_get_sync in amdgpu_driver_unload_kms */
+		if (adev->rmmio && amdgpu_device_is_px(dev))
+			pm_runtime_put_noidle(dev->dev);
 		amdgpu_driver_unload_kms(dev);
-
+	}
 
 	return r;
 }
-- 
2.8.1

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[PATCH 6/9] drm/amdgpu: Don't leak runtime pm ref on driver unload

[Lukas Wunner]

amdgpu_driver_load_kms() calls pm_runtime_put_autosuspend() if
amdgpu_device_is_px(dev), but amdgpu_driver_unload_kms() calls
pm_runtime_get_sync() unconditionally. We therefore leak a runtime pm
ref whenever amdgpu is unloaded on a non-PX machine or if runpm=0. The
GPU will subsequently never runtime suspend after loading amdgpu again.

Fix by taking the runtime pm ref under the same condition that it was
released on driver load.

Fixes: d38ceaf99ed0 ("drm/amdgpu: add core driver (v4)")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
index 40a2370..9b1f979 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
@@ -60,7 +60,9 @@ int amdgpu_driver_unload_kms(struct drm_device *dev)
 	if (adev->rmmio == NULL)
 		goto done_free;
 
-	pm_runtime_get_sync(dev->dev);
+	if (amdgpu_device_is_px(dev)) {
+		pm_runtime_get_sync(dev->dev);
+	}
 
 	amdgpu_amdkfd_device_fini(adev);
 
-- 
2.8.1

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[PATCH 4/9] drm/radeon: Don't leak runtime pm ref on driver load

[Lukas Wunner]

radeon_device_init() returns an error if either of the two calls to
radeon_init() fail. One level up in the call stack,
radeon_driver_load_kms() will then skip runtime pm initialization and
call radeon_driver_unload_kms(), which acquires a runtime pm ref that
is leaked.

Balance by releasing a runtime pm ref in the error path of
radeon_device_init().

Fixes: 10ebc0bc0934 ("drm/radeon: add runtime PM support (v2)")
Cc: Dave Airlie <airlied@redhat.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
---
 drivers/gpu/drm/radeon/radeon_device.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
index e721e6b..e0bf778 100644
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -30,6 +30,7 @@
 #include <drm/drmP.h>
 #include <drm/drm_crtc_helper.h>
 #include <drm/radeon_drm.h>
+#include <linux/pm_runtime.h>
 #include <linux/vgaarb.h>
 #include <linux/vga_switcheroo.h>
 #include <linux/efi.h>
@@ -1505,6 +1506,9 @@ int radeon_device_init(struct radeon_device *rdev,
 	return 0;
 
 failed:
+	/* balance pm_runtime_get_sync() in radeon_driver_unload_kms() */
+	if (radeon_is_px(ddev))
+		pm_runtime_put_noidle(ddev->dev);
 	if (runtime)
 		vga_switcheroo_fini_domain_pm_ops(rdev->dev);
 	return r;
-- 
2.8.1

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[PATCH 2/9] drm/nouveau: Forbid runtime pm on driver unload

[Lukas Wunner]

The PCI core calls pm_runtime_forbid() on device probe in pci_pm_init(),
making this the default state when nouveau is loaded. nouveau_drm_load()
therefore calls pm_runtime_allow(), but there's no pm_runtime_forbid()
in nouveau_drm_unload() to balance it. Add it so that we leave the
device in the same state that we found it.

This isn't a bug, it's just good housekeeping. When nouveau is first
loaded with runpm=1, then unloaded and loaded again with runpm=0,
pm_runtime_forbid() will be called from nouveau_pmops_runtime_idle() or
nouveau_pmops_runtime_suspend(), so the behaviour is correct. The nvidia
blob doesn't use runtime pm, but if it ever does, this commit avoids
that it has to clean up behind nouveau.

Tested-by: Karol Herbst <nouveau@karolherbst.de>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
---
 drivers/gpu/drm/nouveau/nouveau_drm.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
index faf7438..ef784b7 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
@@ -500,6 +500,7 @@ nouveau_drm_unload(struct drm_device *dev)
 
 	if (nouveau_runtime_pm != 0) {
 		pm_runtime_get_sync(dev->dev);
+		pm_runtime_forbid(dev->dev);
 	}
 
 	nouveau_fbcon_fini(dev);
-- 
2.8.1

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[PATCH 9/9] drm: Turn off crtc before tearing down its data structure

[Lukas Wunner]

When a drm_crtc structure is destroyed with drm_crtc_cleanup(), the DRM
core does not turn off the crtc first and neither do the drivers. With
nouveau, radeon and amdgpu, this causes a runtime pm ref to be leaked on
driver unload if at least one crtc was enabled.

(See usage of have_disp_power_ref in nouveau_crtc_set_config(),
radeon_crtc_set_config() and amdgpu_crtc_set_config()).

Fixes: 5addcf0a5f0f ("nouveau: add runtime PM support (v0.9)")
Cc: Dave Airlie <airlied@redhat.com>
Tested-by: Karol Herbst <nouveau@karolherbst.de>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
---
 drivers/gpu/drm/drm_crtc.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index d2a6d95..0cd6f00 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -716,12 +716,23 @@ EXPORT_SYMBOL(drm_crtc_init_with_planes);
  *
  * This function cleans up @crtc and removes it from the DRM mode setting
  * core. Note that the function does *not* free the crtc structure itself,
- * this is the responsibility of the caller.
+ * this is the responsibility of the caller. If @crtc is currently enabled,
+ * it is turned off first.
  */
 void drm_crtc_cleanup(struct drm_crtc *crtc)
 {
 	struct drm_device *dev = crtc->dev;
 
+	if (crtc->enabled) {
+		struct drm_mode_set modeset = {
+			.crtc = crtc,
+		};
+
+		drm_modeset_lock_all(dev);
+		drm_mode_set_config_internal(&modeset);
+		drm_modeset_unlock_all(dev);
+	}
+
 	kfree(crtc->gamma_store);
 	crtc->gamma_store = NULL;
 
-- 
2.8.1

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Re: [Nouveau] [PATCH 9/9] drm: Turn off crtc before tearing down its data structure

[Daniel Vetter]

On Tue, May 24, 2016 at 06:03:27PM +0200, Lukas Wunner wrote:
> When a drm_crtc structure is destroyed with drm_crtc_cleanup(), the DRM
> core does not turn off the crtc first and neither do the drivers. With
> nouveau, radeon and amdgpu, this causes a runtime pm ref to be leaked on
> driver unload if at least one crtc was enabled.
> 
> (See usage of have_disp_power_ref in nouveau_crtc_set_config(),
> radeon_crtc_set_config() and amdgpu_crtc_set_config()).
> 
> Fixes: 5addcf0a5f0f ("nouveau: add runtime PM support (v0.9)")
> Cc: Dave Airlie <airlied@redhat.com>
> Tested-by: Karol Herbst <nouveau@karolherbst.de>
> Signed-off-by: Lukas Wunner <lukas@wunner.de>

This is a core regression, we fixed it again. Previously when unreference
drm_planes the core made sure that it's not longer in use, which had the
side effect of shutting everything off in module unload.

For a bunch of reasons we've stopped doing that, but that turned out to be
a mistake. It's fixed since

commit f2d580b9a8149735cbc4b59c4a8df60173658140
Author: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Date:   Wed May 4 14:38:26 2016 +0200

    drm/core: Do not preserve framebuffer on rmfb, v4.

Your patch shouldn't be needed with that any more. If it still is it's
most likely the fbdev cleanup done too late, but you /should/ get a big
WARNING splat in that case from drm_mode_config_cleanup().
-Daniel

> ---
>  drivers/gpu/drm/drm_crtc.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index d2a6d95..0cd6f00 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -716,12 +716,23 @@ EXPORT_SYMBOL(drm_crtc_init_with_planes);
>   *
>   * This function cleans up @crtc and removes it from the DRM mode setting
>   * core. Note that the function does *not* free the crtc structure itself,
> - * this is the responsibility of the caller.
> + * this is the responsibility of the caller. If @crtc is currently enabled,
> + * it is turned off first.
>   */
>  void drm_crtc_cleanup(struct drm_crtc *crtc)
>  {
>  	struct drm_device *dev = crtc->dev;
>  
> +	if (crtc->enabled) {
> +		struct drm_mode_set modeset = {
> +			.crtc = crtc,
> +		};
> +
> +		drm_modeset_lock_all(dev);
> +		drm_mode_set_config_internal(&modeset);
> +		drm_modeset_unlock_all(dev);
> +	}
> +
>  	kfree(crtc->gamma_store);
>  	crtc->gamma_store = NULL;
>  
> -- 
> 2.8.1
> 
> _______________________________________________
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> Nouveau@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/nouveau

-- 
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Software Engineer, Intel Corporation
http://blog.ffwll.ch
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Re: [Nouveau] [PATCH 9/9] drm: Turn off crtc before tearing down its data structure

[Lukas Wunner]

Good evening Daniel,

On Tue, May 24, 2016 at 11:30:42PM +0200, Daniel Vetter wrote:
> On Tue, May 24, 2016 at 06:03:27PM +0200, Lukas Wunner wrote:
> > When a drm_crtc structure is destroyed with drm_crtc_cleanup(), the DRM
> > core does not turn off the crtc first and neither do the drivers. With
> > nouveau, radeon and amdgpu, this causes a runtime pm ref to be leaked on
> > driver unload if at least one crtc was enabled.
> > 
> > (See usage of have_disp_power_ref in nouveau_crtc_set_config(),
> > radeon_crtc_set_config() and amdgpu_crtc_set_config()).
> > 
> > Fixes: 5addcf0a5f0f ("nouveau: add runtime PM support (v0.9)")
> > Cc: Dave Airlie <airlied@redhat.com>
> > Tested-by: Karol Herbst <nouveau@karolherbst.de>
> > Signed-off-by: Lukas Wunner <lukas@wunner.de>
> 
> This is a core regression, we fixed it again. Previously when unreference
> drm_planes the core made sure that it's not longer in use, which had the
> side effect of shutting everything off in module unload.
> 
> For a bunch of reasons we've stopped doing that, but that turned out to be
> a mistake. It's fixed since
> 
> commit f2d580b9a8149735cbc4b59c4a8df60173658140
> Author: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Date:   Wed May 4 14:38:26 2016 +0200
> 
>     drm/core: Do not preserve framebuffer on rmfb, v4.

Okay, I will test it.

May I ask you a question while you have this topic swapped into your
brain: nouveau, radeon and amdgpu currently hold one runtime pm ref
if any crtc is turned on. I'm pondering how to make this work for
muxed dual GPU laptops. When switching GPUs, the now inactive GPU
should turn off the crtc used by the panel to save power (if it's
*only* used by the panel) and release that runtime pm ref. Likewise,
the now active GPU needs to turn on the crtc used by the panel and
take a runtime pm ref.

The whole thing becomes a bit complicated because MacBook Pros with
Thunderbolt can only drive external displays with their discrete GPU.
So when switching to the integrated GPU, the discrete GPU may turn
off the crtc for the panel but the crtc for the external display needs
to stay alive if it's in use and the GPU may not suspend.

What I have in mind is to change the scheme nouveau/radeon/amdgpu are
currently using by taking a runtime pm ref when enabling a crtc and
releasing it when disabling the crtc. This is different from the status
quo where only a *single* runtime pm ref is taken if *any* crtc is enabled.

Upon switching, the runtime pm ref for the crtc previously used by the
panel is released and the crtc should be turned off. If it was the only
active crtc the GPU automatically goes to sleep.

I'm thinking about putting the pm_runtime_get() and pm_runtime_put()
in the DRM core. (Actually I already have a commit to do just that in
my local repo.) That way we're using less code in nouveau/radeon/amdgpu
because we're doing the runtime pm handling centrally in the core.
I'm wondering if that would impact other DRM drivers negatively.

Basically the idea is to harmonize runtime pm handling among DRM drivers.
What do you think about that?

Thanks,

Lukas

> 
> Your patch shouldn't be needed with that any more. If it still is it's
> most likely the fbdev cleanup done too late, but you /should/ get a big
> WARNING splat in that case from drm_mode_config_cleanup().
> -Daniel
> 
> > ---
> >  drivers/gpu/drm/drm_crtc.c | 13 ++++++++++++-
> >  1 file changed, 12 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> > index d2a6d95..0cd6f00 100644
> > --- a/drivers/gpu/drm/drm_crtc.c
> > +++ b/drivers/gpu/drm/drm_crtc.c
> > @@ -716,12 +716,23 @@ EXPORT_SYMBOL(drm_crtc_init_with_planes);
> >   *
> >   * This function cleans up @crtc and removes it from the DRM mode setting
> >   * core. Note that the function does *not* free the crtc structure itself,
> > - * this is the responsibility of the caller.
> > + * this is the responsibility of the caller. If @crtc is currently enabled,
> > + * it is turned off first.
> >   */
> >  void drm_crtc_cleanup(struct drm_crtc *crtc)
> >  {
> >  	struct drm_device *dev = crtc->dev;
> >  
> > +	if (crtc->enabled) {
> > +		struct drm_mode_set modeset = {
> > +			.crtc = crtc,
> > +		};
> > +
> > +		drm_modeset_lock_all(dev);
> > +		drm_mode_set_config_internal(&modeset);
> > +		drm_modeset_unlock_all(dev);
> > +	}
> > +
> >  	kfree(crtc->gamma_store);
> >  	crtc->gamma_store = NULL;
> >  
> > -- 
> > 2.8.1
> > 
> > _______________________________________________
> > Nouveau mailing list
> > Nouveau@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/nouveau
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
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Re: [PATCH 9/9] drm: Turn off crtc before tearing down its data structure

[Daniel Vetter]

On Wed, May 25, 2016 at 12:07 AM, Lukas Wunner <lukas@wunner.de> wrote:
> Good evening Daniel,
>
> On Tue, May 24, 2016 at 11:30:42PM +0200, Daniel Vetter wrote:
>> On Tue, May 24, 2016 at 06:03:27PM +0200, Lukas Wunner wrote:
>> > When a drm_crtc structure is destroyed with drm_crtc_cleanup(), the DRM
>> > core does not turn off the crtc first and neither do the drivers. With
>> > nouveau, radeon and amdgpu, this causes a runtime pm ref to be leaked on
>> > driver unload if at least one crtc was enabled.
>> >
>> > (See usage of have_disp_power_ref in nouveau_crtc_set_config(),
>> > radeon_crtc_set_config() and amdgpu_crtc_set_config()).
>> >
>> > Fixes: 5addcf0a5f0f ("nouveau: add runtime PM support (v0.9)")
>> > Cc: Dave Airlie <airlied@redhat.com>
>> > Tested-by: Karol Herbst <nouveau@karolherbst.de>
>> > Signed-off-by: Lukas Wunner <lukas@wunner.de>
>>
>> This is a core regression, we fixed it again. Previously when unreference
>> drm_planes the core made sure that it's not longer in use, which had the
>> side effect of shutting everything off in module unload.
>>
>> For a bunch of reasons we've stopped doing that, but that turned out to be
>> a mistake. It's fixed since
>>
>> commit f2d580b9a8149735cbc4b59c4a8df60173658140
>> Author: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
>> Date:   Wed May 4 14:38:26 2016 +0200
>>
>>     drm/core: Do not preserve framebuffer on rmfb, v4.
>
> Okay, I will test it.
>
> May I ask you a question while you have this topic swapped into your
> brain: nouveau, radeon and amdgpu currently hold one runtime pm ref
> if any crtc is turned on. I'm pondering how to make this work for
> muxed dual GPU laptops. When switching GPUs, the now inactive GPU
> should turn off the crtc used by the panel to save power (if it's
> *only* used by the panel) and release that runtime pm ref. Likewise,
> the now active GPU needs to turn on the crtc used by the panel and
> take a runtime pm ref.
>
> The whole thing becomes a bit complicated because MacBook Pros with
> Thunderbolt can only drive external displays with their discrete GPU.
> So when switching to the integrated GPU, the discrete GPU may turn
> off the crtc for the panel but the crtc for the external display needs
> to stay alive if it's in use and the GPU may not suspend.
>
> What I have in mind is to change the scheme nouveau/radeon/amdgpu are
> currently using by taking a runtime pm ref when enabling a crtc and
> releasing it when disabling the crtc. This is different from the status
> quo where only a *single* runtime pm ref is taken if *any* crtc is enabled.
>
> Upon switching, the runtime pm ref for the crtc previously used by the
> panel is released and the crtc should be turned off. If it was the only
> active crtc the GPU automatically goes to sleep.
>
> I'm thinking about putting the pm_runtime_get() and pm_runtime_put()
> in the DRM core. (Actually I already have a commit to do just that in
> my local repo.) That way we're using less code in nouveau/radeon/amdgpu
> because we're doing the runtime pm handling centrally in the core.
> I'm wondering if that would impact other DRM drivers negatively.
>
> Basically the idea is to harmonize runtime pm handling among DRM drivers.
> What do you think about that?

Great idea and should work well with atomic helpers. Kerneldoc even
explains the suggested way to do it, but doesn't go into all details
since e.g. on arm-soc you might have a platform device for each crtc
and each encoder. Lots of the arm drivers do full-blown runtime pm
with atomic, so there's plenty of examples.

Will be fireworks show with legacy drivers (and hence amdgpu&nouveau)
unfortunately because with legacy crtc helpers the ordering of crtc
enable/disable isn't as well-defined, and you might end up accessing
hw without an rpm reference. Maybe possible with a lot of swearing and
some hacks, but "make rpm easy" was a big reason for an entirely
revamped helper design for atomic (among a few other reasons ofc).

Putting rpm get/put calls into the drm core otoh is a complete no-go,
that's a perfect example of the midlayer mistake. The long-term goal
is to entirely decouple the drm core from underlying devices. All the
new arm drivers don't even use the drm_platform.c stuff, it's just
that there's a big pile of existing drivers which will be somewhat
painful to convert. And for pci it's probably impossible due to old
crap like dri1 and agp :(

Cheers, Daniel


>
> Thanks,
>
> Lukas
>
>>
>> Your patch shouldn't be needed with that any more. If it still is it's
>> most likely the fbdev cleanup done too late, but you /should/ get a big
>> WARNING splat in that case from drm_mode_config_cleanup().
>> -Daniel
>>
>> > ---
>> >  drivers/gpu/drm/drm_crtc.c | 13 ++++++++++++-
>> >  1 file changed, 12 insertions(+), 1 deletion(-)
>> >
>> > diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
>> > index d2a6d95..0cd6f00 100644
>> > --- a/drivers/gpu/drm/drm_crtc.c
>> > +++ b/drivers/gpu/drm/drm_crtc.c
>> > @@ -716,12 +716,23 @@ EXPORT_SYMBOL(drm_crtc_init_with_planes);
>> >   *
>> >   * This function cleans up @crtc and removes it from the DRM mode setting
>> >   * core. Note that the function does *not* free the crtc structure itself,
>> > - * this is the responsibility of the caller.
>> > + * this is the responsibility of the caller. If @crtc is currently enabled,
>> > + * it is turned off first.
>> >   */
>> >  void drm_crtc_cleanup(struct drm_crtc *crtc)
>> >  {
>> >     struct drm_device *dev = crtc->dev;
>> >
>> > +   if (crtc->enabled) {
>> > +           struct drm_mode_set modeset = {
>> > +                   .crtc = crtc,
>> > +           };
>> > +
>> > +           drm_modeset_lock_all(dev);
>> > +           drm_mode_set_config_internal(&modeset);
>> > +           drm_modeset_unlock_all(dev);
>> > +   }
>> > +
>> >     kfree(crtc->gamma_store);
>> >     crtc->gamma_store = NULL;
>> >
>> > --
>> > 2.8.1
>> >
>> > _______________________________________________
>> > Nouveau mailing list
>> > Nouveau@lists.freedesktop.org
>> > https://lists.freedesktop.org/mailman/listinfo/nouveau
>>
>> --
>> Daniel Vetter
>> Software Engineer, Intel Corporation
>> http://blog.ffwll.ch



-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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Re: [PATCH 9/9] drm: Turn off crtc before tearing down its data structure

[Lukas Wunner]

Hi Daniel,

On Tue, May 24, 2016 at 11:30:42PM +0200, Daniel Vetter wrote:
> On Tue, May 24, 2016 at 06:03:27PM +0200, Lukas Wunner wrote:
> > When a drm_crtc structure is destroyed with drm_crtc_cleanup(), the DRM
> > core does not turn off the crtc first and neither do the drivers. With
> > nouveau, radeon and amdgpu, this causes a runtime pm ref to be leaked on
> > driver unload if at least one crtc was enabled.
> > 
> > (See usage of have_disp_power_ref in nouveau_crtc_set_config(),
> > radeon_crtc_set_config() and amdgpu_crtc_set_config()).
> > 
> > Fixes: 5addcf0a5f0f ("nouveau: add runtime PM support (v0.9)")
> > Cc: Dave Airlie <airlied@redhat.com>
> > Tested-by: Karol Herbst <nouveau@karolherbst.de>
> > Signed-off-by: Lukas Wunner <lukas@wunner.de>
> 
> This is a core regression, we fixed it again. Previously when unreference
> drm_planes the core made sure that it's not longer in use, which had the
> side effect of shutting everything off in module unload.
> 
> For a bunch of reasons we've stopped doing that, but that turned out to be
> a mistake. It's fixed since
> 
> commit f2d580b9a8149735cbc4b59c4a8df60173658140
> Author: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Date:   Wed May 4 14:38:26 2016 +0200
> 
>     drm/core: Do not preserve framebuffer on rmfb, v4.
> 
> Your patch shouldn't be needed with that any more. If it still is it's
> most likely the fbdev cleanup done too late, but you /should/ get a big
> WARNING splat in that case from drm_mode_config_cleanup().

I tested it and at least with nouveau, the above-mentioned commit does *not*
solve the issue, so patch [9/9] of this series is still needed. I do not get
a WARN splat when unloading nouveau.

Best regards,

Lukas

> 
> > ---
> >  drivers/gpu/drm/drm_crtc.c | 13 ++++++++++++-
> >  1 file changed, 12 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> > index d2a6d95..0cd6f00 100644
> > --- a/drivers/gpu/drm/drm_crtc.c
> > +++ b/drivers/gpu/drm/drm_crtc.c
> > @@ -716,12 +716,23 @@ EXPORT_SYMBOL(drm_crtc_init_with_planes);
> >   *
> >   * This function cleans up @crtc and removes it from the DRM mode setting
> >   * core. Note that the function does *not* free the crtc structure itself,
> > - * this is the responsibility of the caller.
> > + * this is the responsibility of the caller. If @crtc is currently enabled,
> > + * it is turned off first.
> >   */
> >  void drm_crtc_cleanup(struct drm_crtc *crtc)
> >  {
> >  	struct drm_device *dev = crtc->dev;
> >  
> > +	if (crtc->enabled) {
> > +		struct drm_mode_set modeset = {
> > +			.crtc = crtc,
> > +		};
> > +
> > +		drm_modeset_lock_all(dev);
> > +		drm_mode_set_config_internal(&modeset);
> > +		drm_modeset_unlock_all(dev);
> > +	}
> > +
> >  	kfree(crtc->gamma_store);
> >  	crtc->gamma_store = NULL;
> >  
> > -- 
> > 2.8.1
> > 
> > _______________________________________________
> > Nouveau mailing list
> > Nouveau@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/nouveau
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
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Re: [Nouveau] [PATCH 9/9] drm: Turn off crtc before tearing down its data structure

[Daniel Vetter]

On Wed, May 25, 2016 at 12:51 PM, Lukas Wunner <lukas@wunner.de> wrote:
>
> On Tue, May 24, 2016 at 11:30:42PM +0200, Daniel Vetter wrote:
>> On Tue, May 24, 2016 at 06:03:27PM +0200, Lukas Wunner wrote:
>> > When a drm_crtc structure is destroyed with drm_crtc_cleanup(), the DRM
>> > core does not turn off the crtc first and neither do the drivers. With
>> > nouveau, radeon and amdgpu, this causes a runtime pm ref to be leaked on
>> > driver unload if at least one crtc was enabled.
>> >
>> > (See usage of have_disp_power_ref in nouveau_crtc_set_config(),
>> > radeon_crtc_set_config() and amdgpu_crtc_set_config()).
>> >
>> > Fixes: 5addcf0a5f0f ("nouveau: add runtime PM support (v0.9)")
>> > Cc: Dave Airlie <airlied@redhat.com>
>> > Tested-by: Karol Herbst <nouveau@karolherbst.de>
>> > Signed-off-by: Lukas Wunner <lukas@wunner.de>
>>
>> This is a core regression, we fixed it again. Previously when unreference
>> drm_planes the core made sure that it's not longer in use, which had the
>> side effect of shutting everything off in module unload.
>>
>> For a bunch of reasons we've stopped doing that, but that turned out to be
>> a mistake. It's fixed since
>>
>> commit f2d580b9a8149735cbc4b59c4a8df60173658140
>> Author: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
>> Date:   Wed May 4 14:38:26 2016 +0200
>>
>>     drm/core: Do not preserve framebuffer on rmfb, v4.
>>
>> Your patch shouldn't be needed with that any more. If it still is it's
>> most likely the fbdev cleanup done too late, but you /should/ get a big
>> WARNING splat in that case from drm_mode_config_cleanup().
>
> I tested it and at least with nouveau, the above-mentioned commit does *not*
> solve the issue, so patch [9/9] of this series is still needed. I do not get
> a WARN splat when unloading nouveau.

With legacy kms the only way to keep a crtc enabled is to display a
drm_framebuffer on it. And drm_mode_config_cleanup has a WARN_ON if
framebuffers are left behind. There's a bunch of options:
- nouveau somehow manages to keep the crtc on without a framebuffer
- nouveau somehow leaks a drm_framebuffer, but removes it from the fb_list
- something else

There's still no need to forcefully shut down crtc at cleanup time in
the core, this is still a driver bug. So yes your patch might be
needed, but it's not the right fix.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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Re: [PATCH 9/9] drm: Turn off crtc before tearing down its data structure

[Lukas Wunner]

On Wed, May 25, 2016 at 03:43:42PM +0200, Daniel Vetter wrote:
> On Wed, May 25, 2016 at 12:51 PM, Lukas Wunner <lukas@wunner.de> wrote:
> > On Tue, May 24, 2016 at 11:30:42PM +0200, Daniel Vetter wrote:
> >> On Tue, May 24, 2016 at 06:03:27PM +0200, Lukas Wunner wrote:
> >> > When a drm_crtc structure is destroyed with drm_crtc_cleanup(), the DRM
> >> > core does not turn off the crtc first and neither do the drivers. With
> >> > nouveau, radeon and amdgpu, this causes a runtime pm ref to be leaked on
> >> > driver unload if at least one crtc was enabled.
> >> >
> >> > (See usage of have_disp_power_ref in nouveau_crtc_set_config(),
> >> > radeon_crtc_set_config() and amdgpu_crtc_set_config()).
> >> >
> >> > Fixes: 5addcf0a5f0f ("nouveau: add runtime PM support (v0.9)")
> >> > Cc: Dave Airlie <airlied@redhat.com>
> >> > Tested-by: Karol Herbst <nouveau@karolherbst.de>
> >> > Signed-off-by: Lukas Wunner <lukas@wunner.de>
> >>
> >> This is a core regression, we fixed it again. Previously when unreference
> >> drm_planes the core made sure that it's not longer in use, which had the
> >> side effect of shutting everything off in module unload.
> >>
> >> For a bunch of reasons we've stopped doing that, but that turned out to be
> >> a mistake. It's fixed since
> >>
> >> commit f2d580b9a8149735cbc4b59c4a8df60173658140
> >> Author: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> >> Date:   Wed May 4 14:38:26 2016 +0200
> >>
> >>     drm/core: Do not preserve framebuffer on rmfb, v4.
> >>
> >> Your patch shouldn't be needed with that any more. If it still is it's
> >> most likely the fbdev cleanup done too late, but you /should/ get a big
> >> WARNING splat in that case from drm_mode_config_cleanup().
> >
> > I tested it and at least with nouveau, the above-mentioned commit does
> > *not* solve the issue, so patch [9/9] of this series is still needed.
> > I do not get a WARN splat when unloading nouveau.
> 
> With legacy kms the only way to keep a crtc enabled is to display a
> drm_framebuffer on it. And drm_mode_config_cleanup has a WARN_ON if
> framebuffers are left behind. There's a bunch of options:
> - nouveau somehow manages to keep the crtc on without a framebuffer
> - nouveau somehow leaks a drm_framebuffer, but removes it from the fb_list
> - something else

Found it. nouveau_fbcon_destroy() doesn't call drm_framebuffer_remove().
If I add that, the crtc gets properly disabled on unload.

It does call drm_framebuffer_cleanup(). That's why there was no WARN,
drm_mode_config_cleanup() only WARNs if a framebuffer was left on the
mode_config.fb_list.

radeon and amdgpu have the same problem. In fact there are very few
drivers that call drm_framebuffer_remove(): tegra, msm, exynos, omapdrm
and i915 (since Imre Deak's 9d6612516da0).

Should we add a WARN to prevent this? How about WARN_ON(crtc->enabled)
in drm_crtc_cleanup()?

Also, i915 calls drm_framebuffer_unregister_private() before it calls
drm_framebuffer_remove(). This ordering has the unfortunate side effect
that the drm_framebuffer has ID 0 in log messages emitted by
drm_framebuffer_remove():

[   39.680874] [drm:drm_mode_object_unreference] OBJ ID: 0 (3)
[   39.680878] [drm:drm_mode_object_unreference] OBJ ID: 0 (2)
[   39.680884] [drm:drm_mode_object_unreference] OBJ ID: 0 (1)

Best regards,

Lukas

> 
> There's still no need to forcefully shut down crtc at cleanup time in
> the core, this is still a driver bug. So yes your patch might be
> needed, but it's not the right fix.
> -Daniel
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
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Re: [PATCH 9/9] drm: Turn off crtc before tearing down its data structure

[Daniel Vetter]

On Wed, Jun 01, 2016 at 02:36:41PM +0200, Lukas Wunner wrote:
> On Wed, May 25, 2016 at 03:43:42PM +0200, Daniel Vetter wrote:
> > On Wed, May 25, 2016 at 12:51 PM, Lukas Wunner <lukas@wunner.de> wrote:
> > > On Tue, May 24, 2016 at 11:30:42PM +0200, Daniel Vetter wrote:
> > >> On Tue, May 24, 2016 at 06:03:27PM +0200, Lukas Wunner wrote:
> > >> > When a drm_crtc structure is destroyed with drm_crtc_cleanup(), the DRM
> > >> > core does not turn off the crtc first and neither do the drivers. With
> > >> > nouveau, radeon and amdgpu, this causes a runtime pm ref to be leaked on
> > >> > driver unload if at least one crtc was enabled.
> > >> >
> > >> > (See usage of have_disp_power_ref in nouveau_crtc_set_config(),
> > >> > radeon_crtc_set_config() and amdgpu_crtc_set_config()).
> > >> >
> > >> > Fixes: 5addcf0a5f0f ("nouveau: add runtime PM support (v0.9)")
> > >> > Cc: Dave Airlie <airlied@redhat.com>
> > >> > Tested-by: Karol Herbst <nouveau@karolherbst.de>
> > >> > Signed-off-by: Lukas Wunner <lukas@wunner.de>
> > >>
> > >> This is a core regression, we fixed it again. Previously when unreference
> > >> drm_planes the core made sure that it's not longer in use, which had the
> > >> side effect of shutting everything off in module unload.
> > >>
> > >> For a bunch of reasons we've stopped doing that, but that turned out to be
> > >> a mistake. It's fixed since
> > >>
> > >> commit f2d580b9a8149735cbc4b59c4a8df60173658140
> > >> Author: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> > >> Date:   Wed May 4 14:38:26 2016 +0200
> > >>
> > >>     drm/core: Do not preserve framebuffer on rmfb, v4.
> > >>
> > >> Your patch shouldn't be needed with that any more. If it still is it's
> > >> most likely the fbdev cleanup done too late, but you /should/ get a big
> > >> WARNING splat in that case from drm_mode_config_cleanup().
> > >
> > > I tested it and at least with nouveau, the above-mentioned commit does
> > > *not* solve the issue, so patch [9/9] of this series is still needed.
> > > I do not get a WARN splat when unloading nouveau.
> > 
> > With legacy kms the only way to keep a crtc enabled is to display a
> > drm_framebuffer on it. And drm_mode_config_cleanup has a WARN_ON if
> > framebuffers are left behind. There's a bunch of options:
> > - nouveau somehow manages to keep the crtc on without a framebuffer
> > - nouveau somehow leaks a drm_framebuffer, but removes it from the fb_list
> > - something else
> 
> Found it. nouveau_fbcon_destroy() doesn't call drm_framebuffer_remove().
> If I add that, the crtc gets properly disabled on unload.
> 
> It does call drm_framebuffer_cleanup(). That's why there was no WARN,
> drm_mode_config_cleanup() only WARNs if a framebuffer was left on the
> mode_config.fb_list.
> 
> radeon and amdgpu have the same problem. In fact there are very few
> drivers that call drm_framebuffer_remove(): tegra, msm, exynos, omapdrm
> and i915 (since Imre Deak's 9d6612516da0).
> 
> Should we add a WARN to prevent this? How about WARN_ON(crtc->enabled)
> in drm_crtc_cleanup()?
> 
> Also, i915 calls drm_framebuffer_unregister_private() before it calls
> drm_framebuffer_remove(). This ordering has the unfortunate side effect
> that the drm_framebuffer has ID 0 in log messages emitted by
> drm_framebuffer_remove():
> 
> [   39.680874] [drm:drm_mode_object_unreference] OBJ ID: 0 (3)
> [   39.680878] [drm:drm_mode_object_unreference] OBJ ID: 0 (2)
> [   39.680884] [drm:drm_mode_object_unreference] OBJ ID: 0 (1)

Well we must first unregister it before we can remove it, so this is
unavoidable.

Wrt switching from _cleanup to _remove, iirc there was troubles with the
later calling into the fb->funcs->destroy hook. But many drivers have
their fbdev fb embedded into some struct (instead of a pointer like i915),
and then things go sideways badly. That's why you can't just blindly
replace them.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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Re: [Nouveau] [PATCH 9/9] drm: Turn off crtc before tearing down its data structure

[Lukas Wunner]

On Wed, Jun 01, 2016 at 04:40:12PM +0200, Daniel Vetter wrote:
> On Wed, Jun 01, 2016 at 02:36:41PM +0200, Lukas Wunner wrote:
> > On Wed, May 25, 2016 at 03:43:42PM +0200, Daniel Vetter wrote:
> > > On Wed, May 25, 2016 at 12:51 PM, Lukas Wunner <lukas@wunner.de> wrote:
> > > > On Tue, May 24, 2016 at 11:30:42PM +0200, Daniel Vetter wrote:
> > > > > On Tue, May 24, 2016 at 06:03:27PM +0200, Lukas Wunner wrote:
> > > > > > When a drm_crtc structure is destroyed with drm_crtc_cleanup(), the DRM
> > > > > > core does not turn off the crtc first and neither do the drivers. With
> > > > > > nouveau, radeon and amdgpu, this causes a runtime pm ref to be leaked on
> > > > > > driver unload if at least one crtc was enabled.
> > > > > >
> > > > > > (See usage of have_disp_power_ref in nouveau_crtc_set_config(),
> > > > > > radeon_crtc_set_config() and amdgpu_crtc_set_config()).
> > > > > >
> > > > > > Fixes: 5addcf0a5f0f ("nouveau: add runtime PM support (v0.9)")
> > > > > > Cc: Dave Airlie <airlied@redhat.com>
> > > > > > Tested-by: Karol Herbst <nouveau@karolherbst.de>
> > > > > > Signed-off-by: Lukas Wunner <lukas@wunner.de>
> > > 
> > > With legacy kms the only way to keep a crtc enabled is to display a
> > > drm_framebuffer on it. And drm_mode_config_cleanup has a WARN_ON if
> > > framebuffers are left behind. There's a bunch of options:
> > > - nouveau somehow manages to keep the crtc on without a framebuffer
> > > - nouveau somehow leaks a drm_framebuffer, but removes it from the fb_list
> > > - something else
> > 
> > Found it. nouveau_fbcon_destroy() doesn't call drm_framebuffer_remove().
> > If I add that, the crtc gets properly disabled on unload.
> > 
> > It does call drm_framebuffer_cleanup(). That's why there was no WARN,
> > drm_mode_config_cleanup() only WARNs if a framebuffer was left on the
> > mode_config.fb_list.
> > 
> > radeon and amdgpu have the same problem. In fact there are very few
> > drivers that call drm_framebuffer_remove(): tegra, msm, exynos, omapdrm
> > and i915 (since Imre Deak's 9d6612516da0).
> > 
> > Should we add a WARN to prevent this? How about WARN_ON(crtc->enabled)
> > in drm_crtc_cleanup()?
> > 
> > Also, i915 calls drm_framebuffer_unregister_private() before it calls
> > drm_framebuffer_remove(). This ordering has the unfortunate side effect
> > that the drm_framebuffer has ID 0 in log messages emitted by
> > drm_framebuffer_remove():
> > 
> > [   39.680874] [drm:drm_mode_object_unreference] OBJ ID: 0 (3)
> > [   39.680878] [drm:drm_mode_object_unreference] OBJ ID: 0 (2)
> > [   39.680884] [drm:drm_mode_object_unreference] OBJ ID: 0 (1)
> 
> Well we must first unregister it before we can remove it, so this is
> unavoidable.

Yes but drm_framebuffer_free() calls drm_mode_object_unregister()
and is invoked by drm_framebuffer_remove(), so the additional call to
drm_framebuffer_unregister_private() in intel_fbdev_destroy() seems
superfluous. Or is there some reason I'm missing that this needs to
be called before intel_unpin_fb_obj()?


> Wrt switching from _cleanup to _remove, iirc there was troubles with the
> later calling into the fb->funcs->destroy hook. But many drivers have
> their fbdev fb embedded into some struct (instead of a pointer like i915),
> and then things go sideways badly. That's why you can't just blindly
> replace them.

So the options seem to be:

(1) Refactor nouveau, radeon and amdgpu to not embed their framebuffer
    struct in their fbdev struct, so that drm_framebuffer_remove() can
    be used.

(2) Amend each of them to turn off crtcs which are using the fbdev
    framebuffer, duplicating the code in drm_framebuffer_remove().

(3) Split drm_framebuffer_remove(), move the portion to turn off crtcs
    into a separate helper, say, drm_framebuffer_deactivate(), call that
    from nouveau, radeon and amdgpu.

(4) Go back to square one and use patch [9/9] of this series.

Which one would be most preferred? Is there another solution I've missed?

Thanks,

Lukas
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Re: [Nouveau] [PATCH 9/9] drm: Turn off crtc before tearing down its data structure

[Daniel Vetter]

On Fri, Jun 03, 2016 at 09:30:06AM +0200, Lukas Wunner wrote:
> On Wed, Jun 01, 2016 at 04:40:12PM +0200, Daniel Vetter wrote:
> > On Wed, Jun 01, 2016 at 02:36:41PM +0200, Lukas Wunner wrote:
> > > On Wed, May 25, 2016 at 03:43:42PM +0200, Daniel Vetter wrote:
> > > > On Wed, May 25, 2016 at 12:51 PM, Lukas Wunner <lukas@wunner.de> wrote:
> > > > > On Tue, May 24, 2016 at 11:30:42PM +0200, Daniel Vetter wrote:
> > > > > > On Tue, May 24, 2016 at 06:03:27PM +0200, Lukas Wunner wrote:
> > > > > > > When a drm_crtc structure is destroyed with drm_crtc_cleanup(), the DRM
> > > > > > > core does not turn off the crtc first and neither do the drivers. With
> > > > > > > nouveau, radeon and amdgpu, this causes a runtime pm ref to be leaked on
> > > > > > > driver unload if at least one crtc was enabled.
> > > > > > >
> > > > > > > (See usage of have_disp_power_ref in nouveau_crtc_set_config(),
> > > > > > > radeon_crtc_set_config() and amdgpu_crtc_set_config()).
> > > > > > >
> > > > > > > Fixes: 5addcf0a5f0f ("nouveau: add runtime PM support (v0.9)")
> > > > > > > Cc: Dave Airlie <airlied@redhat.com>
> > > > > > > Tested-by: Karol Herbst <nouveau@karolherbst.de>
> > > > > > > Signed-off-by: Lukas Wunner <lukas@wunner.de>
> > > > 
> > > > With legacy kms the only way to keep a crtc enabled is to display a
> > > > drm_framebuffer on it. And drm_mode_config_cleanup has a WARN_ON if
> > > > framebuffers are left behind. There's a bunch of options:
> > > > - nouveau somehow manages to keep the crtc on without a framebuffer
> > > > - nouveau somehow leaks a drm_framebuffer, but removes it from the fb_list
> > > > - something else
> > > 
> > > Found it. nouveau_fbcon_destroy() doesn't call drm_framebuffer_remove().
> > > If I add that, the crtc gets properly disabled on unload.
> > > 
> > > It does call drm_framebuffer_cleanup(). That's why there was no WARN,
> > > drm_mode_config_cleanup() only WARNs if a framebuffer was left on the
> > > mode_config.fb_list.
> > > 
> > > radeon and amdgpu have the same problem. In fact there are very few
> > > drivers that call drm_framebuffer_remove(): tegra, msm, exynos, omapdrm
> > > and i915 (since Imre Deak's 9d6612516da0).
> > > 
> > > Should we add a WARN to prevent this? How about WARN_ON(crtc->enabled)
> > > in drm_crtc_cleanup()?
> > > 
> > > Also, i915 calls drm_framebuffer_unregister_private() before it calls
> > > drm_framebuffer_remove(). This ordering has the unfortunate side effect
> > > that the drm_framebuffer has ID 0 in log messages emitted by
> > > drm_framebuffer_remove():
> > > 
> > > [   39.680874] [drm:drm_mode_object_unreference] OBJ ID: 0 (3)
> > > [   39.680878] [drm:drm_mode_object_unreference] OBJ ID: 0 (2)
> > > [   39.680884] [drm:drm_mode_object_unreference] OBJ ID: 0 (1)
> > 
> > Well we must first unregister it before we can remove it, so this is
> > unavoidable.
> 
> Yes but drm_framebuffer_free() calls drm_mode_object_unregister()
> and is invoked by drm_framebuffer_remove(), so the additional call to
> drm_framebuffer_unregister_private() in intel_fbdev_destroy() seems
> superfluous. Or is there some reason I'm missing that this needs to
> be called before intel_unpin_fb_obj()?
> 
> 
> > Wrt switching from _cleanup to _remove, iirc there was troubles with the
> > later calling into the fb->funcs->destroy hook. But many drivers have
> > their fbdev fb embedded into some struct (instead of a pointer like i915),
> > and then things go sideways badly. That's why you can't just blindly
> > replace them.
> 
> So the options seem to be:
> 
> (1) Refactor nouveau, radeon and amdgpu to not embed their framebuffer
>     struct in their fbdev struct, so that drm_framebuffer_remove() can
>     be used.
> 
> (2) Amend each of them to turn off crtcs which are using the fbdev
>     framebuffer, duplicating the code in drm_framebuffer_remove().
> 
> (3) Split drm_framebuffer_remove(), move the portion to turn off crtcs
>     into a separate helper, say, drm_framebuffer_deactivate(), call that
>     from nouveau, radeon and amdgpu.
> 
> (4) Go back to square one and use patch [9/9] of this series.
> 
> Which one would be most preferred? Is there another solution I've missed?

I think a dedicated turn_off_everything helper would be best. We'd need an
atomic and a legacy version (because hooray), but that would work in all
cases. Relying on the implicit behaviour to turn off everything (strictly
speaking you only need to turn off all the planes, you can leave crtcs on,
and that's what most atomic drivers want really under normal
circumstances) is a bit fragile, and it's also possible to disable fbdev
emulation. If you driver needs everything to be off in module unload, then
it's imo best to explicitly enforce that.

So "(5) Write dedicated helper to turn off everything" is imo the right
fix.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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Re: [Nouveau] [PATCH 9/9] drm: Turn off crtc before tearing down its data structure

[Lukas Wunner]

On Fri, Jun 03, 2016 at 08:21:50PM +0200, Daniel Vetter wrote:
> On Fri, Jun 03, 2016 at 09:30:06AM +0200, Lukas Wunner wrote:
> > On Wed, Jun 01, 2016 at 04:40:12PM +0200, Daniel Vetter wrote:
> > > On Wed, Jun 01, 2016 at 02:36:41PM +0200, Lukas Wunner wrote:
> > > > On Wed, May 25, 2016 at 03:43:42PM +0200, Daniel Vetter wrote:
> > > > > On Wed, May 25, 2016 at 12:51 PM, Lukas Wunner <lukas@wunner.de> wrote:
> > > > > > On Tue, May 24, 2016 at 11:30:42PM +0200, Daniel Vetter wrote:
> > > > > > > On Tue, May 24, 2016 at 06:03:27PM +0200, Lukas Wunner wrote:
> > > > > > > > When a drm_crtc structure is destroyed with drm_crtc_cleanup(), the DRM
> > > > > > > > core does not turn off the crtc first and neither do the drivers. With
> > > > > > > > nouveau, radeon and amdgpu, this causes a runtime pm ref to be leaked on
> > > > > > > > driver unload if at least one crtc was enabled.
> > > > > > > >
> > > > > > > > (See usage of have_disp_power_ref in nouveau_crtc_set_config(),
> > > > > > > > radeon_crtc_set_config() and amdgpu_crtc_set_config()).
> > > > > > > >
> > > > > > > > Fixes: 5addcf0a5f0f ("nouveau: add runtime PM support (v0.9)")
> > > > > > > > Cc: Dave Airlie <airlied@redhat.com>
> > > > > > > > Tested-by: Karol Herbst <nouveau@karolherbst.de>
> > > > > > > > Signed-off-by: Lukas Wunner <lukas@wunner.de>
> > > > > 
> > > > > With legacy kms the only way to keep a crtc enabled is to display a
> > > > > drm_framebuffer on it. And drm_mode_config_cleanup has a WARN_ON if
> > > > > framebuffers are left behind. There's a bunch of options:
> > > > > - nouveau somehow manages to keep the crtc on without a framebuffer
> > > > > - nouveau somehow leaks a drm_framebuffer, but removes it from the fb_list
> > > > > - something else
> > > > 
> > > > Found it. nouveau_fbcon_destroy() doesn't call drm_framebuffer_remove().
> > > > If I add that, the crtc gets properly disabled on unload.
> > > > 
> > > > It does call drm_framebuffer_cleanup(). That's why there was no WARN,
> > > > drm_mode_config_cleanup() only WARNs if a framebuffer was left on the
> > > > mode_config.fb_list.
> > > > 
> > > > radeon and amdgpu have the same problem. In fact there are very few
> > > > drivers that call drm_framebuffer_remove(): tegra, msm, exynos, omapdrm
> > > > and i915 (since Imre Deak's 9d6612516da0).
> > > > 
> > > > Should we add a WARN to prevent this? How about WARN_ON(crtc->enabled)
> > > > in drm_crtc_cleanup()?
> > > > 
> > > > Also, i915 calls drm_framebuffer_unregister_private() before it calls
> > > > drm_framebuffer_remove(). This ordering has the unfortunate side effect
> > > > that the drm_framebuffer has ID 0 in log messages emitted by
> > > > drm_framebuffer_remove():
> > > > 
> > > > [   39.680874] [drm:drm_mode_object_unreference] OBJ ID: 0 (3)
> > > > [   39.680878] [drm:drm_mode_object_unreference] OBJ ID: 0 (2)
> > > > [   39.680884] [drm:drm_mode_object_unreference] OBJ ID: 0 (1)
> > > 
> > > Well we must first unregister it before we can remove it, so this is
> > > unavoidable.
> > 
> > Yes but drm_framebuffer_free() calls drm_mode_object_unregister()
> > and is invoked by drm_framebuffer_remove(), so the additional call to
> > drm_framebuffer_unregister_private() in intel_fbdev_destroy() seems
> > superfluous. Or is there some reason I'm missing that this needs to
> > be called before intel_unpin_fb_obj()?
> > 
> > 
> > > Wrt switching from _cleanup to _remove, iirc there was troubles with the
> > > later calling into the fb->funcs->destroy hook. But many drivers have
> > > their fbdev fb embedded into some struct (instead of a pointer like i915),
> > > and then things go sideways badly. That's why you can't just blindly
> > > replace them.
> > 
> > So the options seem to be:
> > 
> > (1) Refactor nouveau, radeon and amdgpu to not embed their framebuffer
> >     struct in their fbdev struct, so that drm_framebuffer_remove() can
> >     be used.
> > 
> > (2) Amend each of them to turn off crtcs which are using the fbdev
> >     framebuffer, duplicating the code in drm_framebuffer_remove().
> > 
> > (3) Split drm_framebuffer_remove(), move the portion to turn off crtcs
> >     into a separate helper, say, drm_framebuffer_deactivate(), call that
> >     from nouveau, radeon and amdgpu.
> > 
> > (4) Go back to square one and use patch [9/9] of this series.
> > 
> > Which one would be most preferred? Is there another solution I've missed?
> 
> I think a dedicated turn_off_everything helper would be best. We'd need an
> atomic and a legacy version (because hooray), but that would work in all
> cases. Relying on the implicit behaviour to turn off everything (strictly
> speaking you only need to turn off all the planes, you can leave crtcs on,
> and that's what most atomic drivers want really under normal
> circumstances) is a bit fragile, and it's also possible to disable fbdev
> emulation. If you driver needs everything to be off in module unload, then
> it's imo best to explicitly enforce that.
> 
> So "(5) Write dedicated helper to turn off everything" is imo the right
> fix.

Okay I did that and just posted it as v2. Hope I've understood correctly
what you suggested, if not please let me know and I'll rectify in a v3.

Thanks,

Lukas
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[PATCH 1/9] drm/nouveau: Don't leak runtime pm ref on driver unload

[Lukas Wunner]

nouveau_drm_load() calls pm_runtime_put() if nouveau_runtime_pm != 0,
but nouveau_drm_unload() calls pm_runtime_get_sync() unconditionally.
We therefore leak a runtime pm ref whenever nouveau is loaded with
runpm=0 and then unloaded. The GPU will subsequently never runtime
suspend even if nouveau is loaded again with runpm=1.

Fix by taking the runtime pm ref under the same condition that it was
released on driver load.

Fixes: 5addcf0a5f0f ("nouveau: add runtime PM support (v0.9)")
Cc: Dave Airlie <airlied@redhat.com>
Reported-by: Karol Herbst <nouveau@karolherbst.de>
Tested-by: Karol Herbst <nouveau@karolherbst.de>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
---
 drivers/gpu/drm/nouveau/nouveau_drm.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
index 11f8dd9..faf7438 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
@@ -498,7 +498,10 @@ nouveau_drm_unload(struct drm_device *dev)
 {
 	struct nouveau_drm *drm = nouveau_drm(dev);
 
-	pm_runtime_get_sync(dev->dev);
+	if (nouveau_runtime_pm != 0) {
+		pm_runtime_get_sync(dev->dev);
+	}
+
 	nouveau_fbcon_fini(dev);
 	nouveau_accel_fini(drm);
 	nouveau_hwmon_fini(dev);
-- 
2.8.1

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Re: [PATCH 1/9] drm/nouveau: Don't leak runtime pm ref on driver unload

[Peter Wu]

On Tue, May 24, 2016 at 06:03:27PM +0200, Lukas Wunner wrote:
> nouveau_drm_load() calls pm_runtime_put() if nouveau_runtime_pm != 0,
> but nouveau_drm_unload() calls pm_runtime_get_sync() unconditionally.
> We therefore leak a runtime pm ref whenever nouveau is loaded with
> runpm=0 and then unloaded. The GPU will subsequently never runtime
> suspend even if nouveau is loaded again with runpm=1.
> 
> Fix by taking the runtime pm ref under the same condition that it was
> released on driver load.
> 
> Fixes: 5addcf0a5f0f ("nouveau: add runtime PM support (v0.9)")
> Cc: Dave Airlie <airlied@redhat.com>
> Reported-by: Karol Herbst <nouveau@karolherbst.de>
> Tested-by: Karol Herbst <nouveau@karolherbst.de>
> Signed-off-by: Lukas Wunner <lukas@wunner.de>

Looks good, I tested this scenario:

    ru(){ cat /sys/bus/pci/devices/0000\:01:00.0/power/runtime_usage;}
    ru # reports 1
    modprobe nouveau runpm=0
    ru # reports 2
    rmmod nouveau
    ru # reports 1

Without runpm=0 the count drops to 0 in the second step and stays 0 in
the third step. After applying patch 2/9, this correctly reports 1 as
expected (this is the same as manually setting power/control to on).

Peter

> ---
>  drivers/gpu/drm/nouveau/nouveau_drm.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
> index 11f8dd9..faf7438 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_drm.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
> @@ -498,7 +498,10 @@ nouveau_drm_unload(struct drm_device *dev)
>  {
>  	struct nouveau_drm *drm = nouveau_drm(dev);
>  
> -	pm_runtime_get_sync(dev->dev);
> +	if (nouveau_runtime_pm != 0) {
> +		pm_runtime_get_sync(dev->dev);
> +	}
> +
>  	nouveau_fbcon_fini(dev);
>  	nouveau_accel_fini(drm);
>  	nouveau_hwmon_fini(dev);
> -- 
> 2.8.1
> 
> _______________________________________________
> Nouveau mailing list
> Nouveau@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/nouveau

-- 
Kind regards,
Peter Wu
https://lekensteyn.nl
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Re: [PATCH 1/9] drm/nouveau: Don't leak runtime pm ref on driver unload

[Lukas Wunner]

Hi Peter,

On Fri, May 27, 2016 at 03:07:33AM +0200, Peter Wu wrote:
> On Tue, May 24, 2016 at 06:03:27PM +0200, Lukas Wunner wrote:
> > nouveau_drm_load() calls pm_runtime_put() if nouveau_runtime_pm != 0,
> > but nouveau_drm_unload() calls pm_runtime_get_sync() unconditionally.
> > We therefore leak a runtime pm ref whenever nouveau is loaded with
> > runpm=0 and then unloaded. The GPU will subsequently never runtime
> > suspend even if nouveau is loaded again with runpm=1.
> > 
> > Fix by taking the runtime pm ref under the same condition that it was
> > released on driver load.
> > 
> > Fixes: 5addcf0a5f0f ("nouveau: add runtime PM support (v0.9)")
> > Cc: Dave Airlie <airlied@redhat.com>
> > Reported-by: Karol Herbst <nouveau@karolherbst.de>
> > Tested-by: Karol Herbst <nouveau@karolherbst.de>
> > Signed-off-by: Lukas Wunner <lukas@wunner.de>
> 
> Looks good, I tested this scenario:
> 
>     ru(){ cat /sys/bus/pci/devices/0000\:01:00.0/power/runtime_usage;}
>     ru # reports 1
>     modprobe nouveau runpm=0
>     ru # reports 2
>     rmmod nouveau
>     ru # reports 1
> 
> Without runpm=0 the count drops to 0 in the second step and stays 0 in
> the third step. After applying patch 2/9, this correctly reports 1 as
> expected (this is the same as manually setting power/control to on).

How exactly did you reach the situation where the root port didn't wake
up when you tried to load nouveau again? (IRC conversation this week.)

What's happening is, the PCI core will keep unbound devices (i.e.,
without driver) in D0 but the runtime status is allowed to change
to "suspended". So it'll appear to the kernel as if it was suspended
but in reality it stays in D0.

Once runtime pm for PCIe ports gets merged, the root port above the
GPU will indeed go to D3 in such a situation because the check
pm_children_suspended() (called from rpm_check_suspend_allowed())
returns true.

I'm not sure if this is desirable or not. If we keep unbound devices
in D0, should we allow ports above them to go to D3?

In any case, when nouveau is loaded again, local_pci_probe() will
call pm_runtime_get_sync(), which will implicitly set the runtime
status to "active" and which should also wake parents. So how did
you ever reach a point where you loaded nouveau and the root port
stayed asleep? Clearly we have a bug there, question is where.
This shouldn't work only if pm_runtime_forbid() was called on
driver unload.

Thanks for the extensive testing!

Lukas

> 
> Peter
> 
> > ---
> >  drivers/gpu/drm/nouveau/nouveau_drm.c | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
> > index 11f8dd9..faf7438 100644
> > --- a/drivers/gpu/drm/nouveau/nouveau_drm.c
> > +++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
> > @@ -498,7 +498,10 @@ nouveau_drm_unload(struct drm_device *dev)
> >  {
> >  	struct nouveau_drm *drm = nouveau_drm(dev);
> >  
> > -	pm_runtime_get_sync(dev->dev);
> > +	if (nouveau_runtime_pm != 0) {
> > +		pm_runtime_get_sync(dev->dev);
> > +	}
> > +
> >  	nouveau_fbcon_fini(dev);
> >  	nouveau_accel_fini(drm);
> >  	nouveau_hwmon_fini(dev);
> > -- 
> > 2.8.1
> > 
> > _______________________________________________
> > Nouveau mailing list
> > Nouveau@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/nouveau
> 
> -- 
> Kind regards,
> Peter Wu
> https://lekensteyn.nl
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Re: [PATCH 1/9] drm/nouveau: Don't leak runtime pm ref on driver unload

[Peter Wu]

On Sun, May 29, 2016 at 05:50:06PM +0200, Lukas Wunner wrote:
> Hi Peter,
> 
> On Fri, May 27, 2016 at 03:07:33AM +0200, Peter Wu wrote:
> > On Tue, May 24, 2016 at 06:03:27PM +0200, Lukas Wunner wrote:
> > > nouveau_drm_load() calls pm_runtime_put() if nouveau_runtime_pm != 0,
> > > but nouveau_drm_unload() calls pm_runtime_get_sync() unconditionally.
> > > We therefore leak a runtime pm ref whenever nouveau is loaded with
> > > runpm=0 and then unloaded. The GPU will subsequently never runtime
> > > suspend even if nouveau is loaded again with runpm=1.
> > > 
> > > Fix by taking the runtime pm ref under the same condition that it was
> > > released on driver load.
> > > 
> > > Fixes: 5addcf0a5f0f ("nouveau: add runtime PM support (v0.9)")
> > > Cc: Dave Airlie <airlied@redhat.com>
> > > Reported-by: Karol Herbst <nouveau@karolherbst.de>
> > > Tested-by: Karol Herbst <nouveau@karolherbst.de>
> > > Signed-off-by: Lukas Wunner <lukas@wunner.de>
> > 
> > Looks good, I tested this scenario:
> > 
> >     ru(){ cat /sys/bus/pci/devices/0000\:01:00.0/power/runtime_usage;}
> >     ru # reports 1
> >     modprobe nouveau runpm=0
> >     ru # reports 2
> >     rmmod nouveau
> >     ru # reports 1
> > 
> > Without runpm=0 the count drops to 0 in the second step and stays 0 in
> > the third step. After applying patch 2/9, this correctly reports 1 as
> > expected (this is the same as manually setting power/control to on).
> 
> How exactly did you reach the situation where the root port didn't wake
> up when you tried to load nouveau again? (IRC conversation this week.)

Ensure that the pci/pm patches are applied, then:

 0. Unload nouveau (I have blacklisted it for testing).
 1. Enable rpm for the root port and children (control = auto).
 2. Verify in the kernel logs that the devices are sleeping:
        pcieport 0000:00:01.0: power state changed by ACPI to D3cold
 3. (Optional, to rule out issues with delays:) Disable rpm for the
    Nvidia device (control = on).
 4. modprobe nouveau.

The above test with v4.6 + 4 pci/pm patches (8b71f565) gives:

    50.245795 MXM: GUID detected in BIOS
    50.245948    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.GFX0._DSM] at AML address ffffc90000013b11 length 492
    50.246016 ACPI Warning: \_SB.PCI0.GFX0._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20160108/nsarguments-95)
    50.246044    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.GFX0._DSM] at AML address ffffc90000013b11 length 492
    50.246110    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0.PEGP._DSM] at AML address ffffc90000018297 length 1F
    50.246256 ACPI Warning: \_SB.PCI0.PEG0.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20160108/nsarguments-95)
    50.246289    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0.PEGP._DSM] at AML address ffffc90000018297 length 1F
    50.246443 ACPI Warning: \_SB.PCI0.PEG0.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20160108/nsarguments-95)
    50.246457    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0.PEGP._DSM] at AML address ffffc90000018297 length 1F
    50.246932 pci 0000:01:00.0: optimus capabilities: enabled, status dynamic power, hda bios codec supported
    50.247005 VGA switcheroo: detected Optimus DSM method \_SB_.PCI0.PEG0.PEGP handle
    50.247084    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0.PG00._ON] at AML address ffffc9000001086e length 11D
    50.390140 pcieport 0000:00:01.0: power state changed by ACPI to D0
    50.491893    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0._DSW] at AML address ffffc90000010a2d length 1D
    50.492285 pcieport 0000:00:01.0: PME# disabled
    50.492583 nouveau 0000:01:00.0: unknown chipset (ffffffff)
    50.492687 nouveau: probe of 0000:01:00.0 failed with error -12
    50.501990    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0._S0W] at AML address ffffc90000010a8e length 2
    50.502403 pcieport 0000:00:01.0: PME# enabled
    50.502601    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0._DSW] at AML address ffffc90000010a2d length 1D
    50.513005    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0.PG00._OFF] at AML address ffffc90000010994 length 6D
    50.533258 pcieport 0000:00:01.0: power state changed by ACPI to D3cold

(Note that this patch is not included.) When nouveau is operating
normally, I see that _PS0 is also called (which does not happen above).

If you think that mixing power resources with DSM causes this issue, I
also tried to apply my power resources work for nouveau but it gives the
same problem:

    20.183306 MXM: GUID detected in BIOS
    20.183606 ACPI Warning: \_SB.PCI0.GFX0._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20160108/nsarguments-95)
    20.184158 ACPI Warning: \_SB.PCI0.PEG0.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20160108/nsarguments-95)
    20.184547 ACPI Warning: \_SB.PCI0.PEG0.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20160108/nsarguments-95)
    20.185152 pci 0000:01:00.0: optimus capabilities: enabled, status dynamic power, hda bios codec supported
    20.185351 VGA switcheroo: detected Optimus DSM method \_SB_.PCI0.PEG0.PEGP handle
    20.185384 nouveau: detected PR support, will not use DSM
    20.185552 nouveau 0000:01:00.0: enabling device (0000 -> 0003)
    20.185873 nouveau 0000:01:00.0: unknown chipset (ffffffff)
    20.185946 nouveau: probe of 0000:01:00.0 failed with error -12

> What's happening is, the PCI core will keep unbound devices (i.e.,
> without driver) in D0 but the runtime status is allowed to change
> to "suspended". So it'll appear to the kernel as if it was suspended
> but in reality it stays in D0.
> 
> Once runtime pm for PCIe ports gets merged, the root port above the
> GPU will indeed go to D3 in such a situation because the check
> pm_children_suspended() (called from rpm_check_suspend_allowed())
> returns true.
> 
> I'm not sure if this is desirable or not. If we keep unbound devices
> in D0, should we allow ports above them to go to D3?

Maybe Rafael (linux-pm / linux-pci) can answer this question better?
The comments in local_pci_probe, pci_pm_runtime_suspend and
pci_pm_runtime_resume suggest that unbound devices are assumed in D0
which is apparently not the case when runtime PM is enabled.

> In any case, when nouveau is loaded again, local_pci_probe() will
> call pm_runtime_get_sync(), which will implicitly set the runtime
> status to "active" and which should also wake parents. So how did
> you ever reach a point where you loaded nouveau and the root port
> stayed asleep? Clearly we have a bug there, question is where.
> This shouldn't work only if pm_runtime_forbid() was called on
> driver unload.
> 
> Thanks for the extensive testing!
> Lukas

Both devices (root port and Nvidia) were resumed, but somehow the Nvidia
card was not fully initialized/ready (as you can see in the above logs).

Peter

> > 
> > Peter
> > 
> > > ---
> > >  drivers/gpu/drm/nouveau/nouveau_drm.c | 5 ++++-
> > >  1 file changed, 4 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
> > > index 11f8dd9..faf7438 100644
> > > --- a/drivers/gpu/drm/nouveau/nouveau_drm.c
> > > +++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
> > > @@ -498,7 +498,10 @@ nouveau_drm_unload(struct drm_device *dev)
> > >  {
> > >  	struct nouveau_drm *drm = nouveau_drm(dev);
> > >  
> > > -	pm_runtime_get_sync(dev->dev);
> > > +	if (nouveau_runtime_pm != 0) {
> > > +		pm_runtime_get_sync(dev->dev);
> > > +	}
> > > +
> > >  	nouveau_fbcon_fini(dev);
> > >  	nouveau_accel_fini(drm);
> > >  	nouveau_hwmon_fini(dev);
> > > -- 
> > > 2.8.1
> > > 
> > > _______________________________________________
> > > Nouveau mailing list
> > > Nouveau@lists.freedesktop.org
> > > https://lists.freedesktop.org/mailman/listinfo/nouveau
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Re: [PATCH 1/9] drm/nouveau: Don't leak runtime pm ref on driver unload

[Lukas Wunner]

On Mon, May 30, 2016 at 07:03:46PM +0200, Peter Wu wrote:
> On Sun, May 29, 2016 at 05:50:06PM +0200, Lukas Wunner wrote:
> > How exactly did you reach the situation where the root port didn't wake
> > up when you tried to load nouveau again? (IRC conversation this week.)
> 
> Ensure that the pci/pm patches are applied, then:
> 
>  0. Unload nouveau (I have blacklisted it for testing).
>  1. Enable rpm for the root port and children (control = auto).
>  2. Verify in the kernel logs that the devices are sleeping:
>         pcieport 0000:00:01.0: power state changed by ACPI to D3cold
>  3. (Optional, to rule out issues with delays:) Disable rpm for the
>     Nvidia device (control = on).
>  4. modprobe nouveau.
> 
> The above test with v4.6 + 4 pci/pm patches (8b71f565) gives:
> 
>     50.245795 MXM: GUID detected in BIOS
>     50.245948    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.GFX0._DSM] at AML address ffffc90000013b11 length 492
>     50.246016 ACPI Warning: \_SB.PCI0.GFX0._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20160108/nsarguments-95)
>     50.246044    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.GFX0._DSM] at AML address ffffc90000013b11 length 492
>     50.246110    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0.PEGP._DSM] at AML address ffffc90000018297 length 1F
>     50.246256 ACPI Warning: \_SB.PCI0.PEG0.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20160108/nsarguments-95)
>     50.246289    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0.PEGP._DSM] at AML address ffffc90000018297 length 1F
>     50.246443 ACPI Warning: \_SB.PCI0.PEG0.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20160108/nsarguments-95)
>     50.246457    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0.PEGP._DSM] at AML address ffffc90000018297 length 1F
>     50.246932 pci 0000:01:00.0: optimus capabilities: enabled, status dynamic power, hda bios codec supported
>     50.247005 VGA switcheroo: detected Optimus DSM method \_SB_.PCI0.PEG0.PEGP handle
>     50.247084    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0.PG00._ON] at AML address ffffc9000001086e length 11D
>     50.390140 pcieport 0000:00:01.0: power state changed by ACPI to D0
>     50.491893    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0._DSW] at AML address ffffc90000010a2d length 1D
>     50.492285 pcieport 0000:00:01.0: PME# disabled
>     50.492583 nouveau 0000:01:00.0: unknown chipset (ffffffff)
>     50.492687 nouveau: probe of 0000:01:00.0 failed with error -12

I've tested this on a MacBook Pro, which does not have ACPI _PR3
methods for the root port to which the discrete GPU is attached.
The port can thus only suspend to D3hot, not D3cold.

Even without patch [2/9], when unloading nouveau and letting the
root port go to D3hot, the port is subsequently correctly resumed
to D0 when reloading nouveau.

So the issue that you're seeing without patch [2/9] seems to be
specific to Optimus/_PR3 machines. If possible you should try to
get it working without patch [2/9] because that patch is really
optional (as I've written in the commit message). I'm totally
unfamiliar with Optimus but maybe lspci could help to debug this?

Lukas
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Re: [PATCH 1/9] drm/nouveau: Don't leak runtime pm ref on driver unload

[Peter Wu]

On Tue, May 31, 2016 at 01:34:43PM +0200, Lukas Wunner wrote:
> On Mon, May 30, 2016 at 07:03:46PM +0200, Peter Wu wrote:
> > On Sun, May 29, 2016 at 05:50:06PM +0200, Lukas Wunner wrote:
> > > How exactly did you reach the situation where the root port didn't wake
> > > up when you tried to load nouveau again? (IRC conversation this week.)
> > 
> > Ensure that the pci/pm patches are applied, then:
> > 
> >  0. Unload nouveau (I have blacklisted it for testing).
> >  1. Enable rpm for the root port and children (control = auto).
> >  2. Verify in the kernel logs that the devices are sleeping:
> >         pcieport 0000:00:01.0: power state changed by ACPI to D3cold
> >  3. (Optional, to rule out issues with delays:) Disable rpm for the
> >     Nvidia device (control = on).
> >  4. modprobe nouveau.
> > 
> > The above test with v4.6 + 4 pci/pm patches (8b71f565) gives:
> > 
> >     50.245795 MXM: GUID detected in BIOS
> >     50.245948    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.GFX0._DSM] at AML address ffffc90000013b11 length 492
> >     50.246016 ACPI Warning: \_SB.PCI0.GFX0._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20160108/nsarguments-95)
> >     50.246044    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.GFX0._DSM] at AML address ffffc90000013b11 length 492
> >     50.246110    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0.PEGP._DSM] at AML address ffffc90000018297 length 1F
> >     50.246256 ACPI Warning: \_SB.PCI0.PEG0.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20160108/nsarguments-95)
> >     50.246289    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0.PEGP._DSM] at AML address ffffc90000018297 length 1F
> >     50.246443 ACPI Warning: \_SB.PCI0.PEG0.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20160108/nsarguments-95)
> >     50.246457    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0.PEGP._DSM] at AML address ffffc90000018297 length 1F
> >     50.246932 pci 0000:01:00.0: optimus capabilities: enabled, status dynamic power, hda bios codec supported
> >     50.247005 VGA switcheroo: detected Optimus DSM method \_SB_.PCI0.PEG0.PEGP handle
> >     50.247084    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0.PG00._ON] at AML address ffffc9000001086e length 11D
> >     50.390140 pcieport 0000:00:01.0: power state changed by ACPI to D0
> >     50.491893    nseval-0227 ns_evaluate           : **** Execute method [\_SB.PCI0.PEG0._DSW] at AML address ffffc90000010a2d length 1D
> >     50.492285 pcieport 0000:00:01.0: PME# disabled
> >     50.492583 nouveau 0000:01:00.0: unknown chipset (ffffffff)
> >     50.492687 nouveau: probe of 0000:01:00.0 failed with error -12
> 
> I've tested this on a MacBook Pro, which does not have ACPI _PR3
> methods for the root port to which the discrete GPU is attached.
> The port can thus only suspend to D3hot, not D3cold.
> 
> Even without patch [2/9], when unloading nouveau and letting the
> root port go to D3hot, the port is subsequently correctly resumed
> to D0 when reloading nouveau.
> 
> So the issue that you're seeing without patch [2/9] seems to be
> specific to Optimus/_PR3 machines. If possible you should try to
> get it working without patch [2/9] because that patch is really
> optional (as I've written in the commit message). I'm totally
> unfamiliar with Optimus but maybe lspci could help to debug this?

Without 2/9 I can prevent the issue by writing "on" to
/sys/bus/pci/devices/0000:00:01.0/power/control (the PCIe port), but
that effectively gives the same result as applying 2/9.

The problem occurs when the power is lost (by putting the PCIe port in
D3cold). Maybe it is a bug in the PCI core that does not re-initialize
devices under the port, but since a workaround is available (2/9), I
will focus on other issues first. Maybe it is worth to mention this
issue in the commit message for 2/9 though.
-- 
Kind regards,
Peter Wu
https://lekensteyn.nl
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[PATCH 8/9] drm/amdgpu: Forbid runtime pm on driver unload

[Lukas Wunner]

The PCI core calls pm_runtime_forbid() on device probe in pci_pm_init(),
making this the default state when amdgpu is loaded.
amdgpu_driver_load_kms() therefore calls pm_runtime_allow(), but there's
no pm_runtime_forbid() in amdgpu_driver_unload_kms() to balance it. Add
it so that we leave the device in the same state that we found it.

This isn't a bug, it's just good housekeeping. When amdgpu is first
loaded with runpm=1, then unloaded and loaded again with runpm=0,
pm_runtime_forbid() will be called from amdgpu_pmops_runtime_idle() or
amdgpu_pmops_runtime_suspend(), so the behaviour is correct. If there
ever is a third party driver for AMD cards, this commit avoids that it
has to clean up behind amdgpu.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
index 0db692e..38a28d1 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
@@ -62,6 +62,7 @@ int amdgpu_driver_unload_kms(struct drm_device *dev)
 
 	if (amdgpu_device_is_px(dev)) {
 		pm_runtime_get_sync(dev->dev);
+		pm_runtime_forbid(dev->dev);
 	}
 
 	amdgpu_amdkfd_device_fini(adev);
-- 
2.8.1

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